Node, another node, and methods performed thereby for supporting domain name system over constrained application protocol

Abstract

A method performed by a node (111) supporting operation on a Constrained Application Protocol (CoAP), but incapable of supporting operation on a Domain Name System (DNS) protocol. The node (111) encodes (402) a DNS query into a first message (601, 701), which has a format supported by the CoAP. The DNS query is mapped to the CoAP format of the first message (601, 701) based on a mapping scheme. The node (111) then initiates sending (403) the first message (601, 701) to another node (112) operating in the communications network (100). The another node (112) supports operation on the CoAP and on the DNS protocol. The node (111) finally receives (404) a second message (620, 706) from the another node (112), which has the format supported by the CoAP. The second message (620, 706) comprises the DNS response to the sent DNS query. The DNS response is mapped to the CoAP format of the second message (620, 706) based on the mapping scheme.

The invention claimed is: 
     
       1. A method performed by a client node operating in a communications network, the method comprising:
 encoding a Domain Name System (DNS) query into a first Constrained Application Protocol (CoAP) message; 
 sending the first CoAP message to a server node operating in the communications network; and 
 receiving, from the server node, a second CoAP message that includes a DNS response to the DNS query. 
 
     
     
       2. The method according to  claim 1 , further comprising extracting DNS data from the second CoAP message. 
     
     
       3. The method according to  claim 1 , wherein the first CoAP message is sent and the second CoAP message is received using Datagram Transport Layer Security (DTLS) security. 
     
     
       4. The method according to  claim 1 , wherein the first CoAP message comprises, in one or more first option fields of the first CoAP message, at least one of:
 a. an operation type of the DNS query in a first value; 
 b. a Recursion Desired indicator of the DNS query in a second value; 
 c. a name queried by the DNS query in a name option, and 
 d. a type of resource records requested by the DNS query in a type option. 
 
     
     
       5. The method according to  claim 1 , wherein at least a portion of the DNS query is encoded into a payload field of the first CoAP message and/or at least a portion of the DNS response is encoded into a payload field of the second CoAP message. 
     
     
       6. A method performed by a server node operating in a communications network, the method comprising:
 receiving, from a client node operating in the communications network, a first Constrained Application Protocol (CoAP) message that includes a Domain Name System (DNS) query; 
 encoding a DNS response to the DNS query into a second CoAP message; and 
 sending the second CoAP message to the client node. 
 
     
     
       7. The method according to  claim 6 , further comprising:
 processing the received first CoAP message: and 
 determining, based on the processing, that the received first CoAP message includes the DNS query and that the DNS response is to be sent to the client node in a CoAP message, and wherein the encoding is based on the determination. 
 
     
     
       8. The method according to  claim 6 , wherein the first CoAP message is received and the second CoAP message is sent using Datagram Transport Layer Security (DTLS) security. 
     
     
       9. The method according to  claim 6 , wherein the first CoAP message includes, in one or more first option fields of the first CoAP message, at least one of:
 a. an operation type of the DNS query in a first value; 
 b. a Recursion Desired indicator of the DNS query in a second value; 
 c. a name queried by the DNS query in a name option, and 
 d. a type of resource records requested by the DNS query in a type option. 
 
     
     
       10. The method according to  claim 6 , wherein at least a portion of the DNS query is encoded into a payload field of the first CoAP message and/or at least a portion of the DNS response is encoded into a payload field of the second CoAP message. 
     
     
       11. A client node configured to operate in a communications network, the node comprising:
 processing circuitry configured to:
 encode a Domain Name System (DNS) query into a first Constrained Application Protocol (CoAP) message; 
 send the first CoAP message to a server node operating in the communications network; and 
 receive, from the server node, a second CoAP message that includes a DNS response to the DNS query. 
 
 
     
     
       12. The client node according to  claim 11 , wherein the processing circuitry is further configured to extract DNS data from the second CoAP message. 
     
     
       13. The node according to  claim 11 , wherein the processing circuitry is configured to send the first CoAP message, and to receive the second CoAP message, using Datagram Transport Layer Security (DTLS) security. 
     
     
       14. The node according to  claim 11 , wherein the first CoAP message includes, in one or more first option fields of the first CoAP message, at least one of:
 a. an operation type of the DNS query in a first value; 
 b. a Recursion Desired indicator indicator of the DNS query in a second value; 
 c. a name queried by the DNS query in a name option, and 
 d. a type of resource records requested by the DNS query in a type option. 
 
     
     
       15. The node according to  claim 11 , wherein at least a portion of the DNS query is encoded into a payload field of the first CoAP message and/or at least a portion of the DNS response is encoded into a payload field of the second CoAP message. 
     
     
       16. A server node configured to operate in a communications network, the server node comprising:
 processing circuitry configured to:
 receive, from a client node operating in the communications network, a first Constrained Application Protocol (CoAP) message that includes a Domain Name System (DNS) query; 
 encode a DNS response to the DNS query into a second CoAP message; and 
 send the second CoAP message to the client node. 
 
 
     
     
       17. The server node according to  claim 16 , wherein the processing circuitry is further configured to:
 process the first CoAP message; 
 determine, based on the processing, that the first CoAP message comprises the DNS query and that the DNS response is to be sent to the client node in a CoAP message; and 
 encode the DNS query into the second CoAP message based on the determination. 
 
     
     
       18. The server node according to  claim 16 , wherein the processing circuitry is configured to receive the first CoAP message, and to send the second CoAP message, using Datagram Transport Layer Security (DTLS) security. 
     
     
       19. The server node according to  claim 16 , wherein the first CoAP message includes, in one or more first option fields of the first CoAP message, at least one of:
 a. an operation type of the DNS query in a first value; 
 b. a Recursion Desired indicator indicator of the DNS query in a second value; 
 c. a name queried by the DNS query in a name option, and 
 d. a type of resource records requested by the DNS query in a type option. 
 
     
     
       20. The server node according to  claim 16 , wherein at least a portion of the DNS query is encoded into a payload field of the first CoAP message and/or at least a portion of the DNS response is encoded into a payload field of the second CoAP message.